Legion I. SPUMELLARIA, (continued 9)

Habitat.—Pacific, central area, Stations 265 to 268, depth 2700 to 2900 fathoms.

4. Pipetta conus, n. sp.

Cortical shell spindle-shaped, the middle ellipsoidal part gently passing over at both poles into the conical tubes, which attain only half its length. Network irregular, with roundish or subcircular pores, twice to three times as broad as the bars, twelve to sixteen on the half equator. Medullary shell spherical, one-fourth as broad as the cortical. (Differs from the foregoing species in the short conical tubes and the irregular reticulation.)

Dimensions.—Middle part of the cortical shell 0.16 long, 0.13 broad; tubes 0.09 long, 0.05 on the base broad; pores 0.005 to 0.01, bars 0.003. Medullary shell 0.04.

Habitat.—North Pacific, Station 241, depth 2300 fathoms.

Genus 143. Pipettaria,^[182] n. gen.

Definition.—Druppulida with simple ellipsoidal cortical shell and double medullary shell, with two hollow fenestrated tubes opposite on both poles of the main axis.

The genus Pipettaria differs from the foregoing Pipetta only in the duplication of the medullary shell; as in this, the tubular prolongations of the main axis of the cortical shell may be either conical (with closed apex) or cylindrical (with apical opening?).

1. Pipettaria fusaria, n. sp.

Cortical shell spindle-shaped, the middle ellipsoidal part gently passing over on both poles into the conical tubes, which attain about half its length. Pores regular, circular, twice as broad as the bars, sixteen to eighteen on the half equator; pores of the tubes smaller. Both medullary shells spheroidal, compressed. (The appearance of the cortical shell resembles that of Cannartiscus amphiconus, Pl. 39, fig. 19, but without the equatorial constriction.)

Dimensions.—Main axis of the ellipsoid 0.15, equatorial axis 0.13; length of the polar tubes 0.08, basal breadth 0.05; pores of the former 0.008, bars 0.004; diameter of the medullary shells 0.04 and 0.02.

Habitat.—South Pacific, Station 300, depth 1375 fathoms.

2. Pipettaria tubaria, n. sp. (Pl. 39, fig. 15).

Cannartidium tubarium, Haeckel, 1882, Atlas (pl. xxxix. fig. 15).

Cortical shell ellipsoidal, on both poles distinctly separated from the short conical tubes, the length and breadth of which equal the outer medullary shell. In the equatorial plane arises a circle of four to six short conical protuberances, similar to the polar tubes. Pores subregular, circular, or roundish, scarcely broader than the bars, sixteen to twenty on the half equator. Both medullary shells spheroidal, somewhat compressed in the direction of the two poles (as in fig. 18a).

Dimensions.—Main axis of the ellipsoid 0.12, equatorial axis 0.09; pores 0.005, bars 0.004; size of the equatorial protuberances and of the polar tubes 0.02.

Habitat.—Pacific, central area, Station 265, depth 2900 fathoms.

Family XIII. Spongurida, Haeckel (Pl. 48, figs. 6, 7).

Spongurida, Haeckel, 1862, Monogr. d. Radiol., p. 447 (sensu emendato).

Definition.—Prunoidea with spongy ellipsoidal or cylindrical shell, composed wholly or partially of a spongy framework, without equatorial stricture, with or without an enclosed medullary shell.

The family Spongurida comprises, in the sense here restricted, all those Prunoidea in which the ellipsoidal or cylindrical shell is composed wholly or partially of an irregular siliceous framework, not of simple lattice-work. It contains two subfamilies, differing in the absence or presence of a latticed medullary shell in the middle of the central capsule; in the Spongellipsida it is absent, in the Spongodruppida present; the former are most nearly related to the Ellipsida, the latter to the Druppulida, the difference consisting only in the spongy structure of the cortical shell.

In my Monograph (1862, p. 447) the family Spongurida had a much wider extent, comprising also a number of Sphæroidea and Discoidea, agreeing in the spongy structure of the shell. Here we restrict the definition to those spongy Sphærellaria in which the central capsule and the enclosing spongy cortical shell are ellipsoidal or cylindrical, therefore each transverse section is a circle, and each meridional section an ellipse, as in all Prunoidea.

The Cortical Shell in all Spongurida is composed of a delicate framework of irregularly branched and interwoven siliceous threads; commonly this spongy structure is rather dense or compact, but sometimes also very loose. In the simplest form, Spongellipsis, the spongy cortical shell contains a large cavity, in which lies freely the central capsule. In Spongurus this cavity is completely distended by a spongy framework. In this case the solid spongy shell becomes often prolonged, and its original ellipsoidal form passes over into a cylindrical one (as in many Zygartida). Sometimes (particularly in Spongocore, Pl. 48, fig. 6) the cylinder becomes three-jointed by two more or less distinct annular constrictions. Spongocore is distinguished by an outer veil, a thin lattice-lamella, which envelops the spongy shell and is connected with it by radial beams.

The Medullary Shell, absent in the Spongellipsida, is constant in the second subfamily Spongodruppida. It is either a simple latticed shell (Spongodruppa) or double, composed of two concentric latticed shells (Spongoliva); its form is either spherical or ellipsoidal. It lies in the middle of the central capsule, and is connected by radial beams (perforating the membrane of the latter) with the enveloping spongy cortical shell.

In many Spongurida the surface of the shell is armed with radial spines, and in some genera (Spongoprunum, Spongatractus, &c., Pl. 17, fig. 12), on both poles of the main axis, are developed two strong opposite polar spines, as in many other Prunoidea.

The Central Capsule of the Spongurida is either ellipsoidal or cylindrical. Only in Spongellipsis it lies freely in the internal cavity of the spongy shell. In all other genera it is perforated by a part of the skeleton; in the Spongodruppida it contains the simple or double medullary shell, and the radial beams which perforate its membrane and connect the latter with the external spongy cortical shell. In Spongurus and the allied genera (Spongocore, Spongoprunum) the whole central capsule is filled with a spongy framework which also envelops its surface.

Synopsis of the Genera of Spongurida.

I. Subfamily Spongellipsida. (Ellipsoidal shell composed only of a spongy framework without a latticed medullary shell in the centre. Spongy shell with internal cavity. No polar spines, 144. Spongellipsis.

Spongy shell solid, without internal cavity. Without lattice mantle. No polar spines, 145. Spongurus.

With lattice mantle. No polar spines, 146. Spongocore.

Without lattice mantle. Two opposite spines on the poles of the axis, 147. Spongoprunum

II. Subfamily Spongodruppida. (Ellipsoidal shell composed of an outer spongy cortical shell and an inner latticed medullary shell.) Medullary shell simple. No polar spines, 148. Spongodruppa.

Two opposite spines on the poles of the axis, 149. Spongatractus.

Medullary shell double. No polar spines, 150. Spongoliva.

Two opposite spines on the poles of the axis, 151. Spongoxiphus.

I. Subfamily Spongellipsida. (Ellipsoidal shell composed only of a spongy framework without a latticed medullary shell in the centre.

Spongy shell with internal cavity.

No polar spines,

144. Spongellipsis.

Spongy shell solid, without internal cavity.

Without lattice mantle. No polar spines,

145. Spongurus.

With lattice mantle. No polar spines,

146. Spongocore.

Without lattice mantle. Two opposite spines on the poles of the axis,

147. Spongoprunum

II. Subfamily Spongodruppida. (Ellipsoidal shell composed of an outer spongy cortical shell and an inner latticed medullary shell.)

Medullary shell simple.

No polar spines,

148. Spongodruppa.

Two opposite spine on the poles of the axis,

149. Spongatractus.

Medullary shell double.

No polar spines,

150. Spongoliva.

Two opposite spine on the poles of the axis,

151. Spongoxiphus.

Subfamily 1. Spongellipsida, Haeckel.

Definition.—Spongurida with a spongy ellipsoidal or cylindrical shell, without an internal latticed medullary shell.

Genus 144. Spongellipsis,^[183] n. gen.

Definition.—Spongurida with an ellipsoidal or cylindrical spongy shell, containing an internal cavity, without a latticed medullary shell. Polar spines absent.

The genus Spongellipsis embraces those very simple Spongurida in which the ellipsoidal central capsule is enclosed in a spongy cortical shell of the same form. It corresponds, therefore, to Plegmosphæra among the Sphæroidea, to Plegmodiscus among the Discoidea, and to Spongolarcus among the Larcoidea. In some species the ellipsoidal form is prolonged and passes into a cylindrical one.

Subgenus 1. Spongellipsarium, Haeckel.

Definition.—Surface of the shell smooth or rough, without radial spines.

1. Spongellipsis lævis, n. sp.

Shell ellipsoidal, with smooth surface, its spongy wall scarcely one-tenth as thick as the minor axis of the inner cavity. Spongy framework very compact, with small meshes, three to six times as broad as the bars. Proportion of the major axis to the minor = 3 : 2.

Dimensions.—Major axis (or length) of the shell 0.36, minor axis (or breadth) 0.24.

Habitat.—Pacific, central area, Station 265, surface.

2. Spongellipsis aspera, n. sp.

Shell ellipsoidal, with rough surface, its spongy wall nearly half as thick as the minor axis of the inner cavity. Spongy framework very loose, with large meshes, ten to twenty times as broad as the bars. Proportion of the major axis to the minor = 4 : 3.

Dimensions.—Length of the shell 0.24, breadth 0.18.

Habitat.—North Pacific, Station 253, surface.

3. Spongellipsis aplysina, n. sp.

Shell nearly cylindrical, with rough surface, its spongy wall about one-fourth as thick as the minor axis of the internal cavity. Spongy framework loose, with large meshes, four to eight times as broad as the bars. Proportion of both axes = 6 : 1. (Similar to a spongy cylinder of Aplysina.)

Dimensions.—Length of the shell 0.3, breadth 0.05.

Habitat.—North Atlantic, Station 64, surface.

Subgenus 2. Spongellipsidium, Haeckel.

Definition.—Surface of the shell covered with radial spines.

4. Spongellipsis setosa, n. sp.

Shell ellipsoidal, covered with numerous (sixty to eighty) thin, bristle-shaped, radial spines, about half as long as the major axis. Spongy framework loose, with large meshes, ten to twenty times as broad as the bars. Minor axis of the inner cavity twice as long as the thickness of the spongy wall. Proportion of both axes = 5 : 3.

Dimensions.—Length of the shell 0.2, breadth 0.12.

Habitat.—South Atlantic, Station 325, surface.

5. Spongellipsis spinosa, n. sp.

Shell nearly cylindrical, covered with numerous thorns and thirty to forty larger conical radial spines, somewhat longer than the major axis. Spongy framework compact, with small meshes, four to eight times as broad as the bars. Minor axis of the inner cavity about six times as large as the thickness of the spongy wall. Proportion of both axes = 4 : 1.

Dimensions.—Length of the shell 0.24, breadth 0.06.

Habitat.—South Pacific, Station 300, surface.

Genus 145. Spongurus,^[184] Haeckel, 1862, Monogr. d. Radiol., p. 465.

Definition.—Spongurida with ellipsoidal or cylindrical (sometimes three-jointed) shell, of solid spongy framework, without internal cavity and without latticed medullary shell. Polar spines and outer lattice-mantle absent.

The genus Spongurus was founded by me in 1862 for the common cosmopolitan Spongurus cylindricus, a massive spongy cylinder with radial spines. I enlarge here the conception of the genus, in receiving also ellipsoidal, massive spongy Prunoidea, with or without radial spines. Sometimes the cylindrical shell is more or less distinctly three-jointed, with two annular strictures, as also in the following and nearly allied genus.

Subgenus 1. Spongurantha, Haeckel.

Definition.—Spongy framework everywhere of the same structure; surface smooth or rough, but without radial spines.

1. Spongurus stuparius, n. sp.

Shell ellipsoidal, one and a half times as long as broad, with nearly smooth surface. Spongy framework everywhere of equal structure, with small meshes, four to six times as broad as the bars.

Dimensions.—Length of the shell (or major axis) 0.2, breadth of it (or minor axis) 0.14.

Habitat.—South Pacific, Station 295, depth 1500 fathoms.

2. Spongurus stypticus, n. sp.

Shell ellipsoidal, twice as long as broad, with thorny surface. Spongy framework everywhere of equal structure, with large meshes, ten to twenty times as broad as the bars.

Dimensions.—Length of the shell 0.3, breadth 0.15.

Habitat.—Pacific, central area, Station 274, depth 2750 fathoms.

3. Spongurus phalanga, Haeckel.

Spongurus cylindricus, Stöhr, 1880, Palæontogr., vol. xxvi. p. 119, Taf. vii. fig. 3.

Shell nearly cylindrical, five times as long as broad, with thorny surface. Spongy framework compact, everywhere of equal structure, with small meshes, scarcely broader than the bars.

Dimensions.—Length of the shell 0.24, breadth 0.05.

Habitat.—Pacific, central area, Station 268, depth 2600 fathoms; fossil in the Tertiary rocks of Sicily, Stöhr.

Subgenus 2. Spongurella, Haeckel.

Definition.—Spongy framework everywhere of the same structure; surface armed with radial spines.

4. Spongurus asper, Haeckel.

Haliomma asperum, Joh. Müller, 1858, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 40, Taf. ii. fig. 2.

Haliomma asperum, Haeckel, 1862, Monogr. d. Radiol., p. 431.

Shell ellipsoidal, one and a third times as long as broad, with thorny surface and twenty symmetrically disposed, thin, bristle-shaped, radial spines, about as long as the shell. Spongy framework everywhere of the same structure, very compact, with small meshes, three to four times as broad as the bars.

Dimensions.—Length of the shell 0.11, breadth 0.08.

Habitat.—Mediterranean, Ligurian coast (J. Müller), Portofino (Haeckel).

5. Spongurus cylindricus, Haeckel.

Spongurus cylindricus, Haeckel, 1862, Monogr. d. Radiol., p. 465, Taf. xxvii. fig. 1.

Shell cylindrical, four to five times as long as broad, with nearly smooth surface, and twenty to thirty thin, bristle-shaped, radial spines, about half as long as the shell. Spongy framework everywhere of the same structure, very compact, with small meshes, scarcely broader than the bars.

Dimensions.—Length of the shell 0.2, breadth 0.04 to 0.05.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, and Pacific, surface.

6. Spongurus tricolus, n. sp.

Shell nearly cylindrical, with two slight annular transverse strictures; its middle part is somewhat broader. Surface thorny, with numerous (forty to sixty or more) short, thin, radial spines, not longer than the breadth of the shell. Spongy framework everywhere of the same structure, compact, with small meshes, twice to three times as broad as the bars.

Dimensions.—Length of the shell 0.24, breadth 0.04 to 0.06.

Habitat.—Pacific, central area, Station 272, 2600 fathoms.

Subgenus 3. Sponguroma, Haeckel.

Definition.—Spongy framework in the inner part of the shell very compact, in the outer part very loose; surface armed with radial spines.

7. Spongurus radians, n. sp.

Shell ellipsoidal, one and a half times as long as broad, with thorny surface, and eighty to one hundred and twenty (or more) thin, bristle-shaped, radial spines, somewhat longer than the shell. Spongy framework in the inner part very compact, in the outer part very loose, with a gradual transition between the two parts. Meshes in the central part not broader than the bars, in the superficial part ten to twenty times as broad.

Dimensions.—Length of the shell 0.24, breadth 0.16.

Habitat.—Mediterranean, Portofino, near Genoa, Haeckel, surface.

8. Spongurus spongechinus, n. sp.

Shell ellipsoidal, one and a third times as long as broad, with thorny surface, and thirty to forty thick, conical radial spines, about half as long as the shell. Spongy framework in the inner part of the shell compact, in the outer loose, with a gradual transition between the two parts. Meshes in the central part smaller than the bars, in the superficial part four to eight times as broad.

Dimensions.—Length of the shell 0.18, breadth 0.14.

Habitat.—North Atlantic, Station 353, surface.

Genus 146. Spongocore,^[185] n. gen.

Definition.—Spongurida with ellipsoidal or cylindrical (sometimes three-jointed) shell of solid spongy framework, without internal cavity and without latticed medullary shell. Polar spines absent. An outer lattice-mantle is connected with the spongy shell by radial beams.

The genus Spongocore contains some widely distributed Spongurida, which are distinguished from the nearly related Spongurus by the development of a peculiar veil or mantle of delicate lattice-work, which envelops either the whole shell or only the middle part of it, and is connected with it by numerous radial beams. The distance of the simple fine lattice-lamella from the spongy shell is everywhere the same. Often the cylindrical shell is three-jointed, with two annular strictures, as also in the foregoing Spongurus. It is derived from the latter by development of the veil connecting the points of the radial spines.

Subgenus 1. Spongocorina, Haeckel.

Definition.—Shell without distinct annular strictures, not evidently three-jointed.

1. Spongocore velata, n. sp.

Shell ellipsoidal, one and a half times as long as broad, without annular strictures. Spongy framework loose, with rather large meshes, four to six times as broad as the bars. The whole spongy shell enveloped by a delicate veil with smooth surface, connected with it by numerous thin radial beams. Breadth of the spongy ellipsoid (or minor axis) six times as large as its distance from the veil.

Dimensions.—Length of the whole shell (with veil) 0.3, breadth 0.2; distance of the veil from the spongy ellipsoid 0.035.

Habitat.—South Atlantic, Station 325, surface.

2. Spongocore diplocylindrica, n. sp.

Shell cylindrical, three times as long as broad, without annular strictures. Spongy framework compact, with small meshes, twice to three times as broad as the bars. The whole surface of the spongy cylinder, with exception of both rounded polar faces, enveloped by a delicate cylindrical veil with smooth surface, connected with it by numerous radial beams. Diameter of the spongy cylinder twice as large as its distance from the veil.

Dimensions.—Length of the shell 0.3, breadth (with veil) 0.1; distance of the veil 0.025.

Habitat.—South Pacific, Station 302, surface.

Subgenus 2. Spongocorisca, Haeckel.

Definition.—Shell distinctly three-jointed, with two transverse annular strictures.

3. Spongocore chrysalis, n. sp.

Spongy shell cylindrical, without the veil six times as long as broad, three-jointed, with two annular strictures; all three joints of the same length. The whole spongy shell enveloped by a thin veil with thorny surface, connected with it by numerous radial beams. Breadth of the spongy cylinder three times as large as its distance from the veil.

Dimensions.—Length of the shell (with veil) 0.4, breadth 0.1; distance of the veil from the spongy shell 0.02.

Habitat.—South Atlantic (off Patagonia), Station 318, surface.

4. Spongocore cincta, n. sp.

Spongy shell cylindrical, without the veil four times as long as broad, three-jointed, with two annular strictures; all three joints of the same length. Only the middle joint enveloped by a thin veil with smooth surface, connected with it by radial beams. Both terminal joints with long, bristle-shaped, radial spines. Breadth of the spongy cylinder twice as large as its distance from the veil.

Dimensions.—Length of the shell 0.24, breadth (with veil) 0.12; distance of the veil 0.03.

Habitat.—Indian Ocean, Madagascar, Rabbe, surface.

5. Spongocore pupula, n. sp.

Spongy shell cylindrical, without the veil six times as long as broad, three-jointed, with two annular strictures; the middle joint half as long as either terminal joint. Only the middle joint enveloped by a thin veil with spiny surface, connected with it by twenty to thirty radial beams, which are prolonged on the outside into short radial spines. Breadth of the spongy cylinder about equal to its distance from the veil.

Dimensions.—Length of the shell 0.2, breadth (with veil) 0.1; distance of the veil 0.033.

Habitat.—North Pacific, Station 244, surface.

6. Spongocore puella, n. sp. (Pl. 48, fig. 6).

Spongy shell cylindrical, without the veil five times as long as broad, three-jointed, with two annular strictures; the middle joint twice as long as either terminal joint. Only the middle joint enveloped by a thin veil with delicate lattice-work and smooth surface; both terminal joints armed with numerous thin, bristle-shaped, radial spines. Breadth of the spongy cylinder twice as large as the distance from the veil.

Dimensions.—Length of the shell 0.25 to 0.3, breadth (with veil) 0.1 to 0.12; distance of the veil 0.028 to 0.032.

Habitat.—South Pacific, Stations 295 to 304, surface.

Genus 147. Spongoprunum,^[186] n. gen.

Definition.—Spongurida with ellipsoidal or cylindrical shell of solid spongy framework, without internal cavity and without latticed medullary shell. On the poles of the axis occur two opposite strong spines.

The genus Spongoprunum differs from the most nearly allied Spongurus by the possession of two strong solid spines, lying in the axis of the ellipsoidal or cylindrical massive spongy shell, on its two opposite poles. Spongoprunum bears therefore the same relation to Spongurus that Ellipsoxiphus does to Cenellipsis.

1. Spongoprunum amphilonche, n. sp. (Pl. 48, fig. 7).

Shell ellipsoidal, two and a third times as long as broad, with nearly smooth surface. Spongy framework very compact, in the whole solid shell of the same structure, with very small meshes, scarcely broader than the bars. Two polar spines conical, very strong, about half as long as the main axis of the shell and three times as long as broad.

Dimensions.—Length of the shell (without spines) 0.2, breadth 0.08.

Habitat.—Central Pacific, Station 265, depth 2900 fathoms; fossil in the rocks of Barbados.

2. Spongoprunum atractus, n. sp.

Shell spindle-shaped, twice as long as broad, with thorny surface. Spongy framework loose, in the whole shell of the same structure, with large meshes, eight to twelve times as broad as the bars. Two polar spines angular, pyramidal, very strong, about one-third as long as the shell, and twice as long as broad.

Dimensions.—Length of the shell 0.2, breadth 0.11.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

3. Spongoprunum amphicylindrus, n. sp.

Shell nearly cylindrical, four times as long as broad, with rough surface. Spongy framework compact, in the whole shell of equal structure, with small meshes, twice to three times as broad as the bars. Two polar spines cylindrical, very large, longer than the shell, and about one-fourth as thick as its diameter.

Dimensions.—Length of the shell 0.2, breadth 0.05.

Habitat.—South Atlantic, Station 333, surface.

Subfamily Spongodruppida, Haeckel.

Definition.—Spongurida with latticed medullary shell, enclosed by a spongy cortical shell.

Genus 148. Spongodruppa,^[187] n. gen.

Definition.—Spongurida with spongy ellipsoidal cortical shell, enclosing a simple, spherical or ellipsoidal, latticed medullary shell. Polar spines absent.

The genus Spongodruppa opens the series of Spongodruppida, or of those Spongurida in which the ellipsoidal spongy cortical shell encloses a simple or double, latticed, medullary shell. In Spongodruppa, the simplest and probably the ancestral form of this subfamily, the medullary shell is simple and the polar spines absent. It may be derived from Druppula by a spongy thickening of the simple latticed cortical shell.

Subgenus 1. Spongodruppula, Haeckel.

Definition.—Surface of the shell smooth or rough, without radial spines.

1. Spongodruppa terebintha, n. sp.

Cortical shell one and a third times as long as broad, with smooth surface, three times as broad as the spherical medullary shell. Spongy framework very compact, with small meshes of the same breadth as the bars. Thickness of the spongy wall equal to the radius of the medullary shell.

Dimensions.—Length of the cortical shell (or major axis of the ellipsoid) 0.16, breadth (or minor axis) 0.12; thickness of its wall 0.02; medullary shell 0.04.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

2. Spongodruppa pistacia, n. sp.

Cortical shell one and a half times as long as broad, with thorny surface, nearly five times as broad as the spherical medullary shell. Spongy framework compact, its thickness equal to the diameter of the medullary shell.

Dimensions.—Length of the cortical shell 0.2, breadth 0.14; thickness of its wall 0.03; medullary shell 0.03.

Habitat.—Fossil in the rocks of Barbados.

3. Spongodruppa lentisca, n. sp.

Cortical shell twice as long as broad, with rough surface, four times as large as the ellipsoidal medullary shell. Spongy framework loose, with large meshes, its thickness equal to the length of the medullary shell.

Dimensions.—Length of the cortical shell 0.25, breadth 0.13; thickness of its wall 0.06; length of the medullary shell 0.06, breadth 0.04.

Habitat.—Pacific, central area, Station 266, surface.

Subgenus 2. Spongodruppium, Haeckel.

Definition.—Surface of the shell armed with radial spines.

4. Spongodruppa frangula, n. sp.

Cortical shell one and a third times as long as broad, three times as broad as the spherical medullary shell. Spongy framework loose, with large meshes, its thickness half as large as the diameter of the medullary shell. Surface covered with numerous (forty to fifty) thin, bristle-shaped, radial spines, about as long as the cortical shell.

Dimensions.—Length of the cortical shell 0.24, breadth 0.18; thickness of its wall 0.035; diameter of the medullary shell 0.06.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

5. Spongodruppa elliptica, Haeckel.

Acanthosphæra elliptica, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 285, Taf. vii. fig. 4.

Cortical shell nearly twice as long as broad, four times as broad as the ellipsoidal medullary shell. Spongy framework compact, with small meshes. Surface covered with very numerous short radial spines, about as long as the medullary shell.

Dimensions.—Length of the cortical shell 0.2, breadth 0.11; length of the medullary shell 0.04, breadth 0.03.

Habitat.—Philippine Sea, Ehrenberg, Station 206, depth 2100 fathoms.

6. Spongodruppa polyacantha, Haeckel.

Haliomma polyacanthum, J. Müller, 1858, Abhandl., p. 36, Taf. i. figs. 10, 11.

Haliomma polyacanthum, Haeckel, 1862, Monogr. d. Radiol., p. 430.

Cortical shell one and a third times as long as broad, twice as broad as the ellipsoidal medullary shell. Spongy framework loose on the surface, with large regular meshes. Surface covered with fifteen to twenty thick, conical spines, about as long as the radius of the shell.

Dimensions.—Length of the cortical shell 0.12, of the medullary shell 0.09; diameter of the medullary shell 0.05 to 0.06.

Habitat.—Mediterranean (south coast of France); Atlantic (Canary Islands), Station 354, surface.

Genus 149. Spongatractus,^[188] n. gen.

Definition.—Spongurida with spongy ellipsoidal cortical shell, enclosing a simple, spherical or ellipsoidal, latticed medullary shell. On the poles of the axis occur two opposite strong spines.

The genus Spongatractus differs from Spongodruppa by development of two strong spines in the axis of the shell, on its two opposite poles; therefore it bears the same relation to the latter that Lithatractus does to Druppula, and can be derived from Lithatractus by a spongy thickening of the cortical shell.

1. Spongatractus pachystylus, Haeckel.

Spongosphæra pachystyla, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 82, Taf. xxvi. fig. 3.

Cortical shell one and a half times as long as broad, with rough surface. Spongy framework compact, with small meshes, about as thick as the spherical medullary shell. Polar spines very stout, conical, slightly sulcated, about as long as the breadth of the cortical shell, as broad at the base as the medullary shell.

Dimensions.—Length of the cortical shell 0.2, breadth 0.13; thickness of the spongy wall 0.045; diameter of the medullary shell 0.04.

Habitat.—Fossil in the rocks of Barbados, Ehrenberg; living in the Equatorial Atlantic, Station 348, depth (2450) fathoms.

2. Spongatractus fusiformis, n. sp.

Cortical shell one and a third times as long as broad, with nearly smooth surface. Spongy framework very compact, with very small meshes, about as thick as the radius of the spherical medullary shell. Polar spines very strong, three-sided pyramidal, about as long as the breadth of the cortical shell, as broad at the base as the medullary shell.

Dimensions.—Length of the cortical shell 0.16 to 0.18, breadth 0.12 to 0.14; thickness of the spongy wall 0.02; diameter of the medullary shell 0.04.

Habitat.—Pacific, central area, Station 268, depth 2900 fathoms.

3. Spongatractus streptacanthus, n. sp.

Cortical shell twice as long as broad, with thorny surface. Spongy framework loose, with large meshes, about as thick as the ellipsoidal medullary shell. Polar spines very long, three-sided prismatic, with three spirally contorted edges, much longer than the cortical shell, half as broad as the medullary shell.

Dimensions.—Length of the cortical shell 0.25, breadth 0.13; thickness of the spongy wall 0.03; diameter of the medullary shell 0.03 to 0.04.

Habitat.—North Atlantic, off Canary Islands, Haeckel.

Genus 150. Spongoliva,^[189] n. gen.

Definition.—Spongurida with spongy ellipsoidal cortical shell, enclosing a double, spherical or ellipsoidal, latticed medullary shell. Polar spines absent.

The genus Spongoliva differs from the nearest Spongodruppa by duplication of the medullary shell; it bears therefore the same relation to this that Prunulum does to Druppula, and can be regarded as a Prunulum, in which the simple latticed cortical shell is replaced by a spongy framework.

Subgenus 1. Spongolivetta, Haeckel.

Definition.—Surface of the shell smooth or rough, without radial spines.

1. Spongoliva cerasina, n. sp.

Cortical shell one and a fourth times as long as broad, with smooth surface, four times as broad as the outer spherical medullary shell. Spongy framework very compact, with very small meshes, its thickness equal to the diameter of the outer medullary shell.

Dimensions.—Length of the cortical shell 0.2, breadth 0.16; thickness of its wall 0.04; diameter of the outer medullary shell 0.04, of the inner 0.014.

Habitat.—Fossil in the rocks of Barbados.

2. Spongoliva prunulina, n. sp.

Cortical shell one and a third times as long as broad, with smooth surface, three times as large as the outer ellipsoidal medullary shell. Spongy framework very compact, with small meshes, its thickness equal to the diameter of the inner medullary shell.

Dimensions.—Length of the cortical shell 0.24, breadth 0.18; thickness of its wall 0.03; size of the outer medullary shell 0.08 to 0.06, of the inner 0.03.

Habitat.—Pacific, central area, Station 265, depth 2900 fathoms.

3. Spongoliva persicina, n. sp.

Cortical shell one and a half times as long as broad, with rough surface, five to six times as large as the ellipsoidal outer medullary shell. Spongy framework loose, with large meshes, its thickness about equal to the outer medullary shell.

Dimensions.—Length of the cortical shell 0.26, breadth 0.18; thickness of its wall 0.04; size of the outer medullary shell 0.045 to 0.035, of the inner 0.015.

Habitat.—Equatorial Atlantic, Station 348, depth (2450) fathoms.

4. Spongoliva amygdalina, n. sp.

Cortical shell twice as long as broad, with thorny surface, ten times as long as the small spherical outer medullary shell. Spongy framework loose, with large meshes, its thickness one and a half times as large as the outer medullary shell.

Dimensions.—Length of the cortical shell 0.3, breadth 0.16; thickness of its wall 0.045; size of the outer medullary shell 0.03, of the inner 0.015.

Habitat.—Fossil in the Tertiary rocks of Sicily (Caltanisetta).

Subgenus 2. Spongolivina, Haeckel.

Definition.—Surface of the shell armed with radial spines.

5. Spongoliva opuntina, n. sp.

Cortical shell one and a third times as long as broad, armed with numerous thin, bristle-shaped, radial spines, nearly as long as the shell. Spongy framework loose, with large meshes, its thickness nearly equal to the diameter of the outer spherical medullary shell.

Dimensions.—Length of the cortical shell 0.18, breadth 0.14; thickness of its wall 0.035; diameter of the outer medullary shell 0.04, of the inner 0.02.

Habitat.—South Atlantic, Station 325, surface.

6. Spongoliva daturina, n. sp.

Cortical shell one and a half times as long as broad, armed with numerous, thick and short, conical radial spines, about as long as the outer medullary shell. Spongy framework compact, with small meshes, its thickness equal to half the length of the outer ellipsoidal medullary shell.

Dimensions.—Length of the cortical shell 0.24, breadth 0.16; thickness of its wall 0.025; diameter of the outer medullary shell 0.045 to 0.035, of the inner 0.025.

Habitat.—Pacific, central area, Station 272, surface.

Genus 151. Spongoxiphus,^[190] n. gen.

Definition.—Spongurida with spongy ellipsoidal cortical shell, enclosing a double, spherical or ellipsoidal, latticed medullary shell. On the poles of the axis occur two opposite strong spines.

The genus Spongoxiphus differs from Spongoliva by the development of two strong spines in the axis of the shell, on its two opposite poles. From the similar Spongatractus it differs in the duplication of the medullary shell. It may also be regarded as a Stylatractus, in which the simple latticed cortical shell is replaced by an irregular spongy framework.

1. Spongoxiphus sphærococcus, n. sp.

Cortical shell one and a half times as long as broad, with thorny surface. Spongy framework compact, with small meshes, its thickness equal to the radius of the outer medullary shell. Both medullary shells spherical, the outer three times as broad as the inner. Polar spines very stout, conical, slightly sulcated, about half as long as the cortical shell, as broad at the base as the outer medullary shell. (Differs from Spongatractus pachystylus almost only in the double medullary shell.)

Dimensions.—Length of the cortical shell 0.18, breadth 0.12; thickness of the spongy wall 0.025; diameter of the outer medullary shell 0.05, of the inner 0.016.

Habitat.—Fossil in the rocks of Barbados (Haeckel); also living in the Pacific, central area, Station 265, depth 2900 fathoms.

2. Spongoxiphus prunococcus, n. sp. (Pl. 17, figs. 12, 13).

Spongostylus prunococcus, Haeckel, 1881, Prodromus, p. 455, et Atlas, pl. xvii. figs. 12, 13.

Cortical shell one and a third times as long as broad, with smooth surface. Spongy framework very compact, with very small meshes, its thickness about equals the breadth of the outer medullary shell. Both medullary shells ellipsoidal, the outer three times as large as the inner. Polar spines very stout, three-sided pyramidal, about half as long as the cortical shell, on the base about as broad as the outer medullary shell. (Differs from the preceding in the ellipsoidal form of both medullary shells, and in the finer structure of the spongy framework.)

Dimensions.—Length of the cortical shell 0.18 to 0.2, breadth 0.14 to 0.16; thickness of the spongy wall 0.035 to 0.04; length of the outer medullary shell 0.04 to 0.06, breadth 0.03 to 0.04.

Habitat.—Pacific, central area, Stations 265 to 268, depths 2700 to 2900 fathoms.

Family XIV. Artiscida, Haeckel (Pl. 39, figs. 9, 10; Pl. 48, fig. 5).

Artiscida, Haeckel, 1881, Prodromus, p. 462.

Definition.—Prunoidea with an ellipsoidal twin-shell divided by an equatorial stricture into two communicating hemiellipsoidal or hemispherical chambers, without enclosed medullary shell. Central capsule ellipsoidal, with or without equatorial stricture.

The family Artiscida has a simple fenestrated outer shell, like that of the Ellipsida, but differs from these in the presence of an equatorial constriction, by which it assumes a characteristic twin form, somewhat similar to a violin (Pl. 39, figs. 9, 10). From the Cyphinida, which have the same form of the cortical shell, the Artiscida differ in the absence of the medullary shell. It is possible that the Artiscida are descended from the Cyphinida (by loss of the medullary shell), but it is more probable that they arise from the Ellipsida by an annular constriction in the equatorial plane (perhaps the formation of the shell originally took place while the central capsule was undergoing division). Both halves of the twin shell are always of the same size and form. Its outer surface is either smooth or covered with radial spines (Artiscus, Pl. 39, fig. 9). Sometimes on the opposite poles of the main axis are developed solid spines (Stylartus, Pl. 48, fig. 5) or hollow fenestrated tubes (Cannartus, Pl. 39, fig. 10).

The Central Capsule is either simply ellipsoidal, or has also an equatorial constriction, which divides it into two equal halves. It is constantly smaller than the surrounding shell, and separated from its inner surface by a thicker or thinner jelly-mantle, the calymma.

Synopsis of the Genera of Artiscida.

On the poles of the main axis neither solid spines nor hollow tubes, 152. Artiscus.

On the poles of the main axis two solid spines (or bunches of spines), 153. Stylartus.

On the poles of the main axis two hollow fenestrated tubes, 154. Cannartus.

On the poles of the main axis neither solid spines nor hollow tubes,

152. Artiscus.

On the poles of the main axis two solid spines (or bunches of spines),

153. Stylartus.

On the poles of the main axis two hollow fenestrated tubes,

154. Cannartus.

Genus 152. Artiscus,^[191] Haeckel, 1881, Prodromus, p. 462.

Definition.—Artiscida without peculiar polar appendages (without strong solid spines or hollow fenestrated tubes on the poles of the main axis).

The genus Artiscus represents the most simple and primitive form of the Artiscida, and may therefore be regarded as the ancestral form of this subfamily. It resembles an ordinary double loaf, composed of two equal, nearly ellipsoidal fenestrated shells separated by the stricture in the equatorial plane. Artiscus can be derived from Cenellipsis simply by this equatorial constriction. But it can also be derived from Cyphanta by loss of the medullary shell.

Subgenus 1. Artiscium, Haeckel.

Definition.—Surface of the shell smooth or rough, without radial rods or spines.

1. Artiscus paniscus, n. sp.

Pores of the shell regular, hexagonal, four times as broad as the bars; ten to twelve pores on the half meridian, eight to nine on the half equator. Surface smooth. (The network of this species is quite the same as that of the proximal cameræ of Panartus diploconus, Pl. 40, fig. 1.)

Dimensions.—Main axis of the shell 0.12, equatorial axis 0.07; meshes 0.013, bars 0.003.

Habitat.—Pacific, central area, Station 271, depth 2425.

2. Artiscus facetus, n. sp.

Pores of the shell regular, circular, with prominent hexagonal frame, twice as broad as the bars; twenty-two to twenty-four pores on the half meridian, fourteen to fifteen on the half equator. Surface a little thorny. (The shell of this species exhibits nearly the same formation as that of Cyphonium virgineum, Pl. 39, fig. 12, but without enclosed medullary shells.)

Dimensions.—Main axis of the shell 0.15, equatorial axis 0.09; meshes 0.01, bars 0.005.

Habitat.—Pacific, central area, Station 266, depth 2750 fathoms.

3. Artiscus paniculus, n. sp.

Pores of the shell regular, circular, without hexagonal frame, as broad as the bars; fourteen to sixteen pores on the half meridian, ten to eleven on the half equator. Surface quite smooth.

Dimensions.—Main axis of the shell 0.13, equatorial axis 0.06; meshes 0.01, bars 0.01.

Habitat.—Fossil in the Tertiary rocks of Barbados (Haeckel).

4. Artiscus panarius, n. sp.

Pores of the shell irregular, roundish, twice to four times as broad as the bars; sixteen to eighteen pores on the half meridian, twelve to thirteen on the half equator. Surface smooth.

Dimensions.—Main axis of the shell 0.11, equatorial axis 0.06; meshes 0.005 to 0.02, bars 0.001 to 0.004.

Habitat.—Western Tropical Pacific, Station 224, depth 1850 fathoms.

Subgenus 2. Artidium, Haeckel, 1881, Prodromus, p. 462.

Definition.—Surface of the shell covered with radial rods or spines.

5. Artiscus elegans, n. sp.

Pores of the shell regular, circular, with hexagonal frames, twice as broad as the bars; fourteen pores on the half meridian, eight to nine on the half equator. From every corner of the hexagonal frames (between every three pores) starts a thin, three-sided pyramidal spine, twice as large as a pore.

Dimensions.—Main axis 0.13, equatorial axis 0.08; meshes 0.007, bars 0.004; spines 0.015 long.

Habitat.—South Atlantic, Station 332, depth 2200 fathoms.

6. Artiscus nodosus, n. sp. (Pl. 39, fig. 9).

Pores of the shell subregular, circular, without hexagonal frame, three times as broad as the bars; sixteen to eighteen on the half meridian, ten to twelve on the half equator. Irregularly scattered on the whole surface a variable number (twenty-five to thirty in all) of stout short radial spines or rather blunt rods; the length and thickness of these is the same, and equals the size of two to three meshes; its form resembles a truncated six-sided pyramid.

Dimensions.—Main axis 0.11, equatorial axis 0.08; meshes 0.01, bars 0.003; length and thickness of the radial sticks 0.02.

Habitat.—Pacific, central area, Station 272, depth 2600 fathoms.

7. Artiscus hystrix, n. sp.

Pores of the shell irregular, roundish, of very unequal size and dissimilar form, twice to eight times as broad as the bars; ten to fifteen on the half meridian, seven to nine on the half equator. Irregularly scattered on the whole surface a large number of thin conical spines, about as large as the meshes, partly directed radially, partly obliquely. (The shell of this species resembles very much that of Cyphonium ceratospyris (p. 366) = Didymocyrtis ceratospyris, Monogr. d. Radiol., 1862, Taf. xxii. fig. 14, but is without the enclosed inner shells.)

Dimensions.—Main axis 0.12, equatorial axis 0.07; meshes 0.004 to 0.02, bars 0.002 to 0.005; spines 0.01 to 0.02.

Habitat.—Atlantic, Eastern Tropical part, Station 346, surface.

Genus 153. Stylartus,^[192] Haeckel, 1881, Prodromus, p. 462.

Definition.—Artiscida with two strong, solid, polar spines, or two bunches of polar spines, opposite on the two poles of the main axis.

The genus Stylartus differs from Artiscus by the production of two large opposite spines in the main axis, starting from both poles of it; sometimes every spine is surrounded by a group of smaller radial spines. The genus is nearly allied to Ellipsoxiphus (p. 295), and differs from it only in the equatorial stricture of the ellipsoidal shell. But it may also be derived from the similar Cyphinus (Pl. 39, fig. 14) by loss of the medullary shell.

Subgenus 1. Stylartella, Haeckel.

Definition.—On each pole of the main axis only one single large spine.

1. Stylartus bipolaris, n. sp. (Pl. 48, fig. 5).

Shell thick walled, rough; both its chambers nearly spherical, with irregular, roundish pores, twice to four times as broad as the bars; eight to ten on the half equator of each chamber. Polar spines very strong, conical, as long as the greatest breadth.

Dimensions.—Length of the shell (without spines) 0.18, greatest breadth 0.13; length of the polar spines 0.13, basal breadth 0.03.

Habitat.—Western Tropical Pacific, Station 224, depth 1850 fathoms.

2. Stylartus bicuspis, n. sp.

Shell thin walled, smooth, with regular, circular pores, twice as broad as the bars; twelve to fourteen on the half equator of each chamber. Polar spines very stout, straight, three-sided pyramidal, half as long as the shell.

Dimensions.—Length of the shell 0.16, greatest breadth 0.12; length of the polar spines 0.08, basal thickness 0.025.

Habitat.—Pacific, central area. Station 266, depth 2750 fathoms.

Subgenus 2. Stylartura, Haeckel.

Definition.—On each pole of the main axis a bunch of several spines.

3. Stylartus palatus, n. sp.

Shell thick walled, thorny, with irregular, roundish pores, twice to three times as broad as the bars; fifteen to eighteen on the half equator of each chamber. On each pole of the main axis a large conical spine, surrounded by a group of ten to fifteen smaller spines, one-third to two-thirds as long as the breadth of the deep equatorial stricture.

Dimensions.—Length of the shell 0.14, greatest breadth 0.09; length of the polar spines 0.03 to 0.06, basal breadth 0.005 to 0.015.

Habitat.—Indian Ocean, Madagascar, Rabbe, surface.

4. Stylartus penicillus, n. sp.

Shell thin walled, smooth, with irregular, roundish pores, three to four times as broad as the bars; ten to twelve on the half equator of each chamber. On each pole of the main axis a brush-like bunch of twenty to thirty thin conical radial spines, half as long as the shell.

Dimensions.—Length of the shell 0.15, greatest breadth 0.1; length of the polar spines 0.08, basal breadth 0.005.

Habitat.—Equatorial Atlantic, Station 347, surface.

Genus 154. Cannartus,^[193] Haeckel, 1881, Prodromus, p. 462.

Definition.—Artiscida with two hollow polar tubes (fenestrated cylindrical or conical tubuli, opposite on the two poles of the main axis).

The genus Cannartus differs from Artiscus by the production of two opposite hollow tubes on both poles of the main axis. The cavity of the conical or cylindrical fenestrated tubes communicates freely with that of the shell; the network in both is the same. The distal end of the tubes is nearly always broken off, sometimes closed, with a conical apex. Cannartus can be derived either from Pipettella by a transverse equatorial constriction, or from Cannartiscus by the loss of the medullary shell, or from Artiscus by the production of the polar tubes.

1. Cannartus violina, n. sp. (Pl. 39, fig. 10).

Pores of the shell subregular, circular, twice to three times as broad as the bars; eighteen to twenty on the half meridian, fourteen to sixteen on the half equator. Shell-wall in the "tropical zone" of both halves thickened. Polar tubes nearly cylindrical, about as long as the main axis, distal ends broken off.

Dimensions.—Main axis 0.14, equatorial axis 0.09; meshes 0.008, bars 0.003; length of the polar tubes 0.12, breadth 0.02 to 0.03.

Habitat.—Pacific, central area, Station 268, depth 2900 fathoms.

2. Cannartus bitubulus, n. sp.

Pores of the shell regular, circular, hexagonally framed, of the same breadth as the bars; fourteen to sixteen on the half meridian, ten to twelve on the half equator. Polar tubes cylindrical, longer than the main axis, sulcated, distal ends broken off. (Similar to Pipetta tuba, Pl. 39, fig. 7, but with equatorial stricture and without medullary shell.)

Dimensions.—Main axis 0.16, equatorial axis 0.12; meshes and bars 0.006; length of the polar tubes 0.2, breadth 0.025.

Habitat.—South Atlantic, Station 332, depth 2200 fathoms.

3. Cannartus biscottus, n. sp.

Pores of the shell irregular, roundish, twice to three times as broad as the bars; ten to twelve on the half meridian, six to eight on the half equator. Polar tubes conical, shorter than the main axis, with closed apex. (Similar to Cannartidium bicinctum, Pl. 39, fig. 18, but without enclosed medullary shell.)

Dimensions.—Main axis 0.11, equatorial axis 0.07; meshes 0.005 to 0.01, bars 0.003; length of the polar tubes 0.08, breadth on the base 0.03.

Habitat.—Equatorial Atlantic, Station 348, depth 2450 fathoms.

Family XV. Cyphinida, Haeckel (Pl. 39, figs. 11-19).

Cyphinida, Haeckel, 1881, Prodromus, p. 462.

Definition.—Prunoidea with ellipsoidal twin-shell, divided by an equatorial stricture into two communicating hemiellipsoidal or hemispherical chambers; this external twin-shell (cortical shell) is either simple or double, and encloses one or more internal concentric shells (medullary shells). Central capsule ellipsoidal, commonly with an equatorial constriction.

The family Cyphinida have the same characteristic twin-form of the cortical shell as the Artiscida, but differ from them in the presence of a simple or double internal medullary shell, connected with the cortical shell by radial beams. The fenestrated shell is therefore composed of two or more concentric shells as in the Druppulida, but differs from these in the ring-like equatorial constriction.

The Medullary Shell, in the middle of the central capsule, is either single or double, composed of two concentric shells. As in the Druppulida, the form of the medullary shells is either spherical (Pl. 39, fig. 12a) or lenticular, compressed from both poles of the main axis (Pl. 39, fig. 18a); sometimes the inner medullary shell is spherical, the outer lenticular.

The Radial Beams, which connect the medullary shell with the equatorial constriction of the cortical shell, lie either all in the equatorial plane (Pl. 39, fig. 11) or near it on both sides (Pl. 39, figs. 12a, 18a).

The Cortical Shell is commonly simple (Pl. 39, figs. 12, 18), sometimes composed of two concentric shells (Pl. 39, fig. 13), rarely of three. As in the Artiscida, also in the Cyphinida, from both poles of the main axis solid spines or hollow fenestrated tubes are often developed (Pl. 39, figs. 14, 16-18).

The Central Capsule of the Cyphinida (Pl. 39, fig. 13) is of the same form as in the Artiscida, generally ellipsoidal, but with an equatorial ring-like stricture, which divides it into two equal halves. It encloses the simple or double medullary shell, and is perforated by the radial beams starting from this. From the inner surface of the surrounding cortical shell it is separated by a thicker or thinner jelly-layer, the calymma. (Compare also Taf. xxii. fig. 14 of my Monograph, 1862.)

Synopsis of the Genera of Cyphinida.

Cortical shell without peculiar spines or hollow fenestrated tubes on both poles of the main axis. Cortical twin-shell simple Medullary shell simple, 155. Cyphanta.

Medullary shell double, 156. Cyphonium.

Cortical twin-shell double or triple; medullary shell double. Cortical shell double, 157. Cypassis.

Cortical shell triple, 158. Cyphocolpus.

Cortical shell simple, with peculiar spines or hollow fenestrated tubes on both poles of the main axis. Two opposite polar spines (or bunches of spines). Medullary shell simple, 159. Cyphinus.

Medullary shell double, 160. Cyphinidium.

Two opposite hollow fenestrated polar tubes. Medullary shell simple, 161. Cannartiscus.

Medullary shell double, 162. Cannartidium.

Cortical shell without peculiar spines or hollow fenestrated tubes on both poles of the main axis.

Cortical twin-shell simple

Medullary shell simple,

155. Cyphanta.

Medullary shell double,

156. Cyphonium.

Cortical twin-shell double or triple; medullary shell double.

Cortical shell double,

157. Cypassis.

Cortical shell triple,

158. Cyphocolpus.

Cortical shell simple, with peculiar spines or hollow fenestrated tubes on both poles of the main axis.

Two opposite polar spines (or bunches of spines).

Medullary shell simple,

159. Cyphinus.

Medullary shell double,

160. Cyphinidium.

Two opposite hollow fenestrated polar tubes.

Medullary shell simple,

161. Cannartiscus.

Medullary shell double,

162. Cannartidium.

Genus 155. Cyphanta,^[194] n. gen.

Definition.—Cyphinida with simple cortical shell and simple medullary shell, without polar spines or tubes.

The genus Cyphanta is the most simple of all Cyphinida, and can be regarded as the common ancestral form of this family. It may be derived phylogenetically from Druppula by a ring-like constriction in the equatorial plane of the ellipsoidal cortical shell, or from Artiscus by secondary formation of a central (spherical or ellipsoidal) medullary shell.

Subgenus 1. Cyphantella, Haeckel.

Definition.—Surface of the cortical shell smooth, without spines or thorns.

1. Cyphanta colpodes, n. sp.

Cortical shell thin walled, with smooth surface; its pores regular, hexagonal, three to four times as broad as the bars; ten to twelve on the half meridian, seven to eight on the half equator. Medullary shell spherical, its diameter one-third of the equatorial axis of the cortical shell. (The cortical shell of this species is nearly identical with the central half of the cortical shell of Panartus diploconus, Pl. 40, fig. 1.)

Dimensions.—Main axis of the cortical shell 0.12, equatorial axis 0.07; meshes 0.013; bars 0.003; diameter of the medullary shell 0.025.

Habitat.—South Pacific, Station 285, depth 2375 fathoms.

2. Cyphanta circopora, n. sp.

Cortical shell thick walled, with smooth surface; pores subregular, circular, twice as broad as the bars; eighteen to twenty on the half meridian, twelve to fourteen on the half equator. Medullary shell spherical, its diameter one-half of the equatorial axis of the cortical shell. (The shell of this species is very similar to that of Cannartiscus amphiconiscus, Pl. 39, fig. 19, but without the polar tubes of that species.)

Dimensions.—Main axis of the cortical shell 0.13, equatorial axis 0.08; meshes 0.007, bars 0.003; diameter of the medullary shell 0.04.

Habitat.—Pacific, central area. Station 266, depth 2750 fathoms.

3. Cyphanta lævis, Haeckel.

Ommatospyris lævis, Ehrenberg, 1872, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 318.

Cortical shell thin walled, with smooth surface; pores of it irregular, roundish, of very different size (some very large in the tropical circles of both hemispheres). Pores twice to six times as broad as the bars; ten to twelve on the half meridian, six to eight on the half equator. Medullary shell spheroidal, compressed, its main axis somewhat shorter than its equatorial axis, which attains half the length of that of the cortical shell. (This species may be perhaps identical with Ommatospyris lævis of Ehrenberg, the diagnosis of which is insufficient and figure not given.)

Dimensions.—Main axis of the cortical shell 0.1, equatorial axis 0.06; meshes 0.005 to 0.02, bars 0.002 to 0.04; diameter of the medullary shell 0.03.

Habitat.—Philippine Sea (Ehrenberg), Station 213, depths 2650 and 3300 fathoms.

4. Cyphanta arachnoides, n. sp.

Cortical shell very delicate and thin walled, cobweb-like, with smooth surface; pores irregular, polygonal (mostly pentagonal or hexagonal), eight to ten times as broad as the thread-like bars; ten to twelve on the half meridian, six to eight on the half equator. Medullary shell spheroidal, compressed, its main axis shorter than its equatorial axis, which is about one-third that of the cortical shell. (This species is very similar to the middle part of the shell of Ommatocampe profundissima, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, Taf. viii. fig. 6.)

Dimensions.—Main axis of the cortical shell 0.11, equatorial axis 0.06; meshes 0.01 to 0.02, bars 0.002; diameter of the medullary shell 0.02.

Habitat.—Atlantic, Canary Islands (Lanzerote), surface.

Subgenus 2. Cyphantissa, Haeckel.

Definition.—Surface of the cortical shell spiny, everywhere scattered with numerous thorns or spines.

5. Cyphanta hispida, n. sp.

Cortical shell thick walled, with spiny surface; pores regular, circular, with hexagonal frame, twice as broad as the bars; twelve to fourteen on the half meridian, eight to ten on the half equator. From the corners of the hexagonal frames (between every three pores) arise short, straight, conical radial spines, somewhat longer than the breadth of the pores. Medullary shell subspherical, its diameter about one-third of the equatorial axis of the cortical shell. (The appearance of the cortical shell is the same as that of the middle part of Peripanartus amphiconus, Pl. 40, fig. 5.)

Dimensions.—Main axis of the cortical shell 0.12, equatorial axis 0.07; meshes 0.01, bars 0.005; length of the spines 0.012; diameter of the medullary shell 0.02.

Habitat.—Pacific, central area, Station 274, depth 2750 fathoms.

6. Cyphanta hystrix, n. sp.

Cortical shell thin walled, with thorny surface; pores irregular, roundish, of very unequal size, twice to six times as broad as the bars; twelve to eighteen on the half meridian, eight to thirteen on the half equator. Between the pores irregularly scattered, bristle-like, thin spines about the same size, partly straight, partly oblique, rising from the surface. Medullary shell lenticular, compressed, its equatorial axis one and a half times the length of the main axis, and about half that of the cortical shell.

Dimensions.—Main axis of the cortical shell 0.15, equatorial axis 0.09; meshes 0.004 to 0.02, bars 0.003 to 0.006; length of the spines 0.02; diameter of the medullary shell 0.04.

Habitat.—South Atlantic, Station 318, surface.

Genus 156. Cyphonium,^[195] n. gen.

Definition.—Cyphinida with simple cortical shell and double medullary shell, without polar spines or tubes.

The genus Cyphonium contains a number of very common species, among which are the earliest known forms of this family, partly described by Ehrenberg as Ommatospyris (which genus contains also a number of other Prunoidea), partly by me (1862) as Didymocyrtis. Both names are inadequate, as allusions to quite different families of Nassellaria, but may be retained as significations of subgeneric divisions. Cyphonium differs from Cyphanta by the double medullary shell, which is either spherical or lenticular.

Subgenus 1. Ommatospyris, Ehrenberg (partim).

Definition.—Surface of the cortical shell smooth, without thorns or spines.

1. Cyphonium coscinoides, n. sp.

Ommatospyris coscinoides, Haeckel, 1881, Prodromus, p. 462.

Cortical shell thin walled, with smooth surface; pores regular, hexagonal, three to four times as broad as the bars; five to six on the half meridian, eight to nine on the half equator of each chamber. Medullary shells both spherical. (The cortical shell of this species is nearly the same as that of Cyphanta colpodes, and as the middle part of the cortical shell of Panartus diploconus, Pl. 40, fig. 1.)

Dimensions.—Main axis of the cortical shell 0.11, equatorial axis 0.06; greatest breadth of the chambers 0.08; pores 0.013, bars 0.003.

Habitat.—North Pacific, Station 244, surface.

2. Cyphonium virgineum, n. sp. (Pl. 39, figs. 12, 12a).

Ommatospyris virginea, Haeckel, 1881, Prodromus et Atlas (pl. xxxix. fig. 12a).

Cortical shell thick walled, with smooth surface (sometimes a little rough with very small thorns); pores subregular, circular, with hexagonal elevated frames, about as broad as the bars; ten to twelve on the half meridian, sixteen to eighteen on the half equator of each chamber. Medullary shells (fig. 12a) both spherical. (Sometimes, as in the figured specimen, the shell is somewhat irregular, an individual abnormality.)

Dimensions.—Main axis of the cortical shell 0.13 to 0.15; equatorial axis of the structure 0.08 to 0.09, of each chamber 0.1 to 0.12, pores and bars 0.005 to 0.007.

Habitat.—Pacific, western tropical part, Station 225, depth 4475 fathoms.

3. Cyphonium ethmarium, n. sp.

Ommatospyris ethmaria, Haeckel, 1881, Prodromus, p. 462.

Cortical shell thin walled, with quite smooth surface; pores subregular, circular (without hexagonal frame), twice as broad as the bars; nine to ten on the half meridian of each chamber, sixteen to eighteen on its half equator. Medullary shells both spherical. (This species resembles the proximal internal chambers of Peripanartus atractus, Pl. 40, fig. 7.)

Dimensions.—Main axis 0.13, equatorial axis 0.07; greatest breadth 0.09; pores 0.006, bars 0.003.

Habitat.—Equatorial Atlantic, Station 347, surface.

4. Cyphonium trinacrium, n. sp.

Cortical shell thick walled, with rough surface; pores subregular, circular (without hexagonal frame), not broader than the bars; five to six on the half meridian of each chamber, nine to ten on its half equator. Medullary shells both compressed, lenticular. This species resembles Cypassis entomocora vel Ommatocampe trinacria, Stöhr, 1880, loc. cit., p. 90, Taf. ii. fig. 1, but has not its external mantle. It may be the ancestral form of it (both in an ontogenetic and phylogenetic sense).

Dimensions.—Main axis 0.11, equatorial axis 0.07; greatest breadth 0.08; pores 0.005, bars 0.005.

Habitat.—Fossil in Tertiary rocks of Sicily, Caltanisetta, Haeckel (Grotte, Stöhr?).

5. Cyphonium diattus, n. sp.

Cortical shell thin walled, with quite smooth surface; pores irregular, polygonal, mostly pentagonal or hexagonal, three to six times as broad as the bars; six to seven on the half meridian of the chamber, ten to twelve on its half equator. Medullary shells both spherical. (Resembles Cyphonium profundum, Ehrenberg, 1872, loc. cit., Taf. x. fig. 5, but does not possess the spines of the surface.)

Dimensions.—Main axis 0.13, equatorial axis 0.06; greatest breadth 0.08; pores 0.005 to 0.012, bars 0.002 to 0.004.

Habitat.—Indian Ocean, western part (Zanzibar), Pullen, depth 2200 fathoms.

6. Cyphonium mammarium, n. sp.

Cortical shell thick walled, with smooth surface (sometimes a little rough); pores irregular, roundish, twice to three times as broad as the bars; eleven to twelve on the half meridian of each chamber, sixteen to nineteen on its half equator. Internal medullary shell spherical, external lenticular compressed, sometimes both spherical or both compressed. (Resembles the internal cortical twin-shell of Cyphocolpus virginis, Pl. 40, fig. 11.)

Dimensions.—Main axis 0.14, equatorial axis 0.08, greatest breadth 0.09; pores 0.004 to 0.006, bars 0.002.

Habitat.—South Pacific, Station 285, depth 2375 fathoms.

Subgenus 2. Ommatocyrtis, Haeckel.

Definition.—Surface of the cortical shell thorny or spiny.

7. Cyphonium hexagonium, n. sp.

Didymocyrtis hexagonia, Haeckel, 1881, Prodromus.

Cortical shell thin walled, with spiny surface; pores regular or subregular, hexagonal, twice to three times as broad as the bars; five to six on the half meridian, nine to ten on the half equator of each chamber. Radial spines between them conical, about as long as the pores. Medullary shells both spherical.

Dimensions.—Main axis 0.14, equatorial axis 0.08; greatest breadth of each chamber 0.1; pores 0.012, bars 0.004.

Habitat.—Pacific, central area, Station 268, depth 2900 fathoms.

8. Cyphonium facettarium, n. sp.

Didymocyrtis facettaria Haeckel, 1881, Prodromus.

Cortical shell thick walled, with spiny surface; pores subregular, circular, with elevated hexagonal frames, twice as broad as the bars; eight to nine on the half meridian, fourteen to sixteen on the half equator of each chamber. In the corners of the hexagons (between every three meshes) arise radial spines, about twice as long as the pores. Both medullary shells spheroidal compressed. (This species is nearly identical with the internal cortical twin-shell of Peripanartus amphiconiscus, Pl. 40, fig. 5.)

Dimensions.—Main axis 0.12, equatorial axis 0.07; greatest breadth of both chambers 0.09; pores 0.01, bars 0.005, spines 0.02.

Habitat.—Western Tropical Pacific, Station 225, depth 4475 fathoms.

9. Cyphonium cribellum, n. sp. (Pl. 39, fig. 11).

Cortical shell thick walled, with spiny surface; pores regular, circular, about as broad as the bars; seven to eight on the half meridian of each chamber, thirteen to fifteen on its half equator. Radial spines between them conical, twice as long as the pores. Medullary shells both lenticular.

Dimensions.—Main axis 0.11, equatorial axis 0.06; greatest breadth 0.08; pores and bars 0.004.

Habitat.—North Atlantic, Station 353, surface.

10. Cyphonium profundum, Haeckel.

Ommatospyris profunda, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 297, Taf. viii. fig. 5, Taf. x. fig. 5.

Cortical shell thin walled, with thorny surface; pores irregular, polygonal, three to six times as broad as the thin bars; five to six on the half meridian of each chamber, ten to twelve on its half equator. Thorns of the surface short. Medullary shells both spherical.

Dimensions.—Main axis 0.1, equatorial axis 0.06; greatest breadth 0.07; pores 0.005 to 0.012, bars 0.002, spines 0.005.

Habitat.—Pacific, tropical zone; Philippine Sea, depth 3300 fathoms, Ehrenberg; Stations 266 to 274, depth 2350 to 2925 fathoms.

11. Cyphonium ceratospyris, Haeckel.

Didymocyrtis ceratospyris, Haeckel, 1862, Monogr. d. Radiol., p. 445, pl. xxii. figs. 14-16.

Haliomma didymocyrtis, Haeckel, 1860, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 816.

Cortical shell thin walled, with spiny surface; pores irregular, roundish, three to nine times as broad as the bars; five to six on the half meridian of each chamber, eight to nine on its half equator. Spines of the surface partly very short, partly as long as the largest pores, either radially or obliquely inserted. Medullary shells both spherical. (Compare the detailed description and figures also of the soft body in my Monograph, loc. cit.)

Dimensions.—Main axis of the cortical shell 0.12, equatorial axis (in the stricture) 0.06; greatest breadth 0.08; pores 0.03 to 0.2, bars 0.002 to 0.006, spines 0.05 to 0.015.

Habitat.—Mediterranean (Messina), Canary Islands (Lanzerote), Haeckel.

Genus 157. Cypassis,^[196] n. gen.

Definition.—Cyphinida with double cortical shell and double medullary shell, without polar spines or tubes.

The genus Cypassis differs from Cyphonium by duplication of the cortical twin-shell; from the outer surface of the simple twin-shell arise numerous radial spines, which become connected by anastomosing transverse branches, and in this manner form an outer envelope or mantle. Cypassis may also be regarded as a Cromyodruppa, the double cortical shell of which is constricted in the equatorial plane.

Subgenus 1. Didymospyris, Haeckel (1881).

Definition.—Surface of the shell smooth, without thorns or spines.

1. Cypassis palliata, n. sp.

Inner cortical shell thin walled, with regular, circular, hexagonally-framed pores, twice as broad as the bars; seven to eight on the half meridian of each chamber, ten to twelve on its half equator. Outer cortical shell very thin, with smooth surface, and very small, irregular, roundish pores, twice to five times smaller than those of the inner shell. Distance between the two cortical shells equals the diameter of the outer medullary shell, which, like the inner, is spherical. (The network of this species resembles that of Peripanartus amphiconiscus, Pl. 40, fig. 5.)

Dimensions.—Main axis of the external cortical shell 0.18, of the internal 0.12; greatest breadth (in the equator of each chamber) of the former 0.13, of the latter 0.09; pores of the outer 0.002 to 0.005, of the inner shell 0.01, bars 0.002 to 0.005.

Habitat.—South Pacific, Station 288, surface.

2. Cypassis eucolpos, n. sp.

Inner cortical shell thick walled, with regular, circular pores, twice as broad as the bars (without hexagonal frames); nine to ten on the half meridian of each chamber, fifteen to seventeen on its half equator. Outer cortical shell very thin, with smooth surface, and very small, irregular, roundish pores, twice to three times smaller than those of the inner shell. Distance between the two cortical shells about one and a half times the diameter of the inner medullary shell, which, like the outer, is spherical. (The inner cortical shell resembles that of Cannartiscus amphiconiscus, Pl. 39, fig. 19, but without polar tubes.)

Dimensions.—Main axis of the external cortical shell 0.2, of the internal 0.15; greatest breadth of the former 0.16, of the latter 0.12; pores of the outer 0.002, of the inner 0.006, bars 0.003.

Habitat.—South Atlantic, Station 319, surface.

Subgenus 2. Didymocyrtis, Haeckel (1862).

Definition.—Surface of the cortical shell thorny or spiny.

3. Cypassis entomocora, Haeckel.

Astromma entomocora, Ehrenberg, 1847, Mikrogeol., Taf. xxii. fig. 32.

Haliomma didymum, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 83.

? Haliomma amphisiphon, Ehrenberg, 1844, Monatsber. d. k. Akad. d. Wiss. Berlin, p. 267.

Ommatospyris entomocora, Ehrenberg, 1875, Abhandl. d. k. Akad. d. Wiss. Berlin, pp. 66, 74.

? Ommatocampe trinacria, Stöhr, 1880, Palæontogr., vol. xxvi. p. 90, Taf. ii. fig. 1.

Didymospyris entomocora, Haeckel, 1881, Prodromus.

Didymocyrtis entomocora, Haeckel, 1862, Monogr. d. Radiol., p. 445.

Inner cortical shell thick walled, with regular, circular pores, twice as broad as the bars (without hexagonal frames); eight to nine on the half meridian of each chamber, ten to eleven on its half equator. Outer cortical shell thin walled, with regular, circular pores like those of the inner. Distance between the two cortical shells equals about twice the diameter of one pore (or the short axis of the lenticular double medullary shell). Surface covered with short conical spines (in the figure of Ehrenberg broken off).

Dimensions.—Main axis of the external cortical shell 0.2, of the internal 0.15; greatest breadth of the former 0.13, of the latter 0.1; pores of the outer 0.005 to 0.01, of the inner 0.01, bars 0.004; length of the surface spines 0.005 to 0.01.

Habitat.—Fossil in the Tertiary rocks of Barbados, Bermuda, and Sicily (Caltanisetta); also living in the greatest depth of the Pacific, Stations 268, 225, depth 2900 to 4475.

4. Cypassis puella, n. sp. (Pl. 39, fig. 13).

Didymospyris colpodes, Haeckel, 1881, Prodromus et Atlas (pl. xxxix., fig. 13).

Internal cortical shell thin walled, with irregular, circular pores of very different size, once to four times as broad as the bars; fourteen to fifteen on the half meridian of each chamber, eighteen to twenty on its half equator. Outer cortical shell thin walled, with irregular, circular pores, only one-third to one-half as large as those of the inner. Distance between the two shells equals the largest diameter of the double lenticular medullary shell. Surface of both cortical shells covered with short conical spines (not longer than the largest pores).

Dimensions.—Main axis of the external cortical shell 0.2, of the internal 0.15, of the central capsule 0.1; greatest breadth of the first 0.14, of the second 0.1, of the third 0.07; pores of the outer shell 0.001 to 0.005, of the inner 0.002 to 0.01, bars 0.002 to 0.003; length of the surface spines 0.005 to 0.01.

Habitat.—Pacific, central area; Stations 266 to 274, surface; Atlantic, Canary Islands (Haeckel), Station 354, surface.

5. Cypassis halicora, n. sp.

Internal cortical shell thin walled, with irregular, roundish pores, once to three times as broad as the bars; ten to eleven on half meridian of each chamber, fourteen to sixteen on its half equator. Outer cortical shell thin walled, with very delicate network, spindle-like, with conical prolongations at both poles. Distance between the two shells larger than the greatest diameter of the double lenticular medullary shell. Surface of both cortical shells covered with innumerable small thorns. (Resembles closely Cyphocolpus virginis, Pl. 40, fig. 11, but without the third shell.)

Dimensions.—Main axis of the external cortical shell 0.21, of the internal 0.14, greatest breadth of the former 0.13, of the later 0.09; pores 0.003 to 0.009; bars of the outer shell 0.001, of the inner 0.004.

Habitat.—Indian Ocean, Ceylon (Haeckel), surface.

Genus 158. Cyphocolpus,^[197] n. gen.

Definition.—Cyphinida with triple cortical shell and double medullary shell, without polar spines or tubes.

The genus Cyphocolpus differs from both foregoing genera by the increased number of the cortical twin-shells. Whilst these are simple in Cyphonium, double in Cypassis, they are triple in Cyphocolpus, composed of three concentric envelopes. The three genera named represent a phylogenetic series, which is repeated in the ontogenetic development of Cyphocolpus.

1. Cyphocolpus didymus, n. sp.

Inner cortical shell with circular, subregular pores, twice as broad as the bars; five to six on the half meridian of each chamber, eight to ten on its half equator. Middle cortical shell also with subregular, circular pores of the same size. Outer cortical shell with smooth surface, with more irregular, roundish pores of very different size. The distance between every two shells equals the diameter of the inner medullary shell, which, like the outer, is spheroidal.

Dimensions.—Main axis of the outer cortical shell 0.3, of the middle 0.22, of the inner 0.15; greatest breadth of the inner cortical shell 0.1, its pores 0.01, bars 0.005.

Habitat.—Indian Ocean, Madagascar, Rabbe, surface.

2. Cyphocolpus virginis, n. sp. (Pl. 40, fig. 11).

Zygartus virginis, Haeckel, 1881, Prodromus et Atlas (pl. xl. fig. 11).

Inner cortical shell with irregular, roundish pores, twice to three times as broad as the bars; eleven to twelve on the half meridian of each chamber, sixteen to eighteen on its half equator. Middle cortical shell with very delicate network, its irregular, polygonal pores of the same size as those of the inner, but separated by extremely thin bars. Outer cortical shell with spiny surface, and with more irregular, roundish pores of different size. The distance between each two shells is variable, and attains more than the diameter of the outer medullary shell, which, like the inner, is spheroidal, slightly compressed.

Dimensions.—Main axis of the outer cortical shell 0.26, of the middle 0.22, of the inner 0.14; greatest breadth of the inner cortical shell 0.09, its pores 0.004 to 0.006, bars 0.002.

Habitat.—Pacific, central area, Station 271, surface.

Genus 159. Cyphinus,^[198] Haeckel, 1881, Prodromus, p. 463.

Definition.—Cyphinida with simple cortical shell and simple medullary shell, with two opposite polar spines (or bunches of polar spines) on the poles of the main axis.

The genus Cyphinus differs from Cyphanta by the development of two opposite spines (or bunches of spines) on both poles of the main axis. It simulates therefore the bipolar formation of Stylartus, and differs from this in the possession of a medullary shell.

Subgenus 1. Cyphinoma, Haeckel.

Definition.—On both poles of the main axis only one single large spine.

1. Cyphinus amphacanthus, n. sp.

Cortical shell with smooth surface, and circular, regular pores, twice as broad as the bars; five to six pores on the half meridian of each chamber, ten to twelve on its half equator. On both poles of the main axis, one single, very strong, conical spine, about half as long as this axis, and half as broad at the base as the spherical medullary shell.

Dimensions.—Main axis of the cortical shell (without spines) 0.2, greatest breadth (in the equator of each chamber) 0.1; pores 0.006, bars 0.003; length of the polar spines 0.1, basal thickness of them 0.02.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

2. Cyphinus dixiphus, n. sp.

Cortical shell with rough surface, and irregular, roundish pores, twice to four times as broad as the bars; eight to nine pores on the half meridian of each chamber, twelve to fourteen on its half equator. On both poles of the main axis, one single, strong, conical spine, with prominent edges at the base, and nearly as broad as the spherical medullary shell, nearly as long as the main axis.

Dimensions.—Main axis (without spines) 0.18, greatest breadth 0.13; pores 0.003 to 0.008, bars 0.002; length of the polar spines 0.16, basal thickness 0.03.

Habitat.—South Pacific, Station 295, depth 1500 fathoms.

Subgenus 2. Cyphinura, Haeckel.

Definition.—On both poles of the main axis a bunch or circle of several spines.

3. Cyphinus amphilophus, n. sp. (Pl. 39, fig. 14).

Cyphinidium amphilophus, Haeckel, 1882, Atlas (pl. xxxix. fig. 14).

Cortical shell thick walled, with rough surface, and subregular, circular pores of different size, twice to five times as broad as the bars; nine to ten pores on the half meridian of each chamber, twelve to fourteen on its half equator. On both poles of the main axis a bunch of six to eight strong conical spines, the largest of which are about as long as the greatest breadth of the shell; their basal part is furrowed, and nearly half as thick as the spherical medullary shell.

Dimensions.—Main axis of the cortical shell (without spines) 0.18 to 0.2, greatest breadth 0.1 to 0.12; pores 0.004 to 0.01, bars 0.002; length of the polar spines 0.04 to 0.12, basal thickness 0.02 to 0.04.

Habitat.—Pacific, central area, Station 271, depth 2425 fathoms.

4. Cyphinus penicillatus, Haeckel.

Ommatospyris penicillata, Ehrenberg, 1872, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 318; Abhandl. d. k. Akad. d. Wiss. Berlin, Taf. viii. fig. 4.

Cortical shell thin walled, with rough surface, and irregular, polygonal pores, six to eight times as broad as the bars; five to six pores on the half meridian of each chamber, nine to ten on its half equator. Around both poles of the main axis a polar circle of eight to ten divergent radial spines, scarcely thicker than the bars, and about as long as the diameter of the spherical medullary shell. (In the figure of Ehrenberg the network is too thin and the spines too short.)

Dimensions.—Main axis (without spines) 0.1, greatest breadth 0.09; pores 0.008 to 0.014, bars 0.001 to 0.002; length of the spines 0.02 to 0.04.

Habitat.—Pacific, Philippine Sea, 3300 fathoms, Ehrenberg; Station 206, depth 2100 fathoms.

Genus 160. Cyphinidium,^[199] n. gen.

Definition.—Cyphinida with simple cortical shell and double medullary shell, with two opposite polar spines (or bunches of polar spines) on the poles of the main axis.

The genus Cyphinidium differs from Cyphinus only in the duplication of the medullary shell, which is composed of two concentric spheres or somewhat compressed lenticular spheroids. It exhibits therefore the same relation to Cyphinus that Stylatractus in the Druppulida bears to Lithatractus. Possibly the two former genera are derived from the two latter by an annular constriction in the equatorial plane.

Subgenus 1. Cyphinidoma, Haeckel.

Definition.—On both poles of the cortical shell one single polar spine or a bunch of polar spines.

1. Cyphinidium amphistylium, n. sp.

Cortical shell thick walled, with smooth surface, and subregular, circular pores, twice to three times as broad as the bars; eight to ten on the half meridian, sixteen to eighteen on the half equator of each chamber. Both medullary shells spherical. The cortical shell resembles very much that of Cannartiscus amphiconiscus (Pl. 39, fig. 19), but exhibits instead of the hollow polar tubes two strong solid polar spines of conical form, half as long as the main axis, and as broad at the base as the inner medullary shell.

Dimensions.—Main axis of the cortical shell (without polar spines) 0.14, greatest breadth 0.1; pores 0.008, bars 0.004; length of the polar spines 0.08, basal thickness 0.02.

Habitat.—North Pacific, off Japan, Station 241, depth 2300 fathoms.

2. Cyphinidium apicatum, Haeckel.

Ommatospyris apicata, Ehrenberg, 1872, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 317.

Cortical shell thin walled, with thorny surface, and irregular, polygonal pores, three to five times as broad as the thin bars; eight to nine on the half meridian, thirteen to fifteen on the half equator of each chamber. On both poles a bunch of four to eight strong conical spines, the central of which (in the main axis) is much larger than the others, and twice as long as the diameter of the outer spheroidal medullary shell; size and number of the polar spines is very variable (commonly five to six).

Dimensions.—Main axis (without spines) 0.12, greatest breadth 0.08; pores 0.005 to 0.01, bars 0.002; length of the polar spines 0.02 to 0.06, basal thickness 0.01.

Habitat.—Northern Pacific, Californian Sea, depth 2500 fathoms, Ehrenberg; Station 253, depth 3125 fathoms.

Subgenus 2. Cyphinidura, Haeckel.

Definition.—On both poles of the cortical shell, a circle of divergent polar spines.

3. Cyphinidium coronatum, n. sp.

Cortical shell with thorny surface, and irregular, roundish pores, twice to four times as broad as the bars; seven to eight on the half meridian, eleven to thirteen on the half equator of each chamber. Around both poles of the main axis occurs a circle of ten to twelve strong, radially divergent spines, about as long as the diameter of the outer medullary shell, which, like the inner, is spheroidal. (This species is identical with the younger developmental stage of Panicium coronatum, Pl. 40, fig. 4, before the formation of two distal chambers.)

Dimensions.—Main axis 0.12, greatest breadth 0.1; pores 0.008 to 0.016, bars 0.004; length of the polar spines 0.02, thickness 0.005.

Habitat.—Pacific, central area, Stations 270 to 274, depth 2350 to 2925 fathoms.

Genus 161. Cannartiscus,^[200] n. gen.

Definition.—Cyphinida with simple cortical shell and simple medullary shell, with two hollow fenestrated polar tubes, opposite on both poles of the main axis.

The genus Cannartiscus differs from Cyphanta in the development of two hollow fenestrated tubes, opposite on both poles of the main axis. It simulates therefore the characteristic formation of Cannartus, and differs from this Artiscid in the possession of a medullary shell.

1. Cannartiscus amphiconiscus, n. sp. (Pl. 39, fig. 19).

Cannartidium amphiconiscus, Haeckel, 1882, Atlas (pl. xxxix. fig. 19).

Cortical shell thick walled, smooth, with regular, circular pores, twice as broad as the bars; nine to ten on the half meridian, sixteen to eighteen on the half equator of each chamber. Polar tubes conical, about as long as one single chamber, on the base somewhat broader than the simple spherical medullary shell. Pores of the tubes only one-third as great as those of the chambers.

Dimensions.—Main axis of the cortical shell (without tubes) 0.14, greatest breadth 0.1; pores 0.008, bars 0.004. Length of the polar tubes 0.07, basal breadth 0.04; pores 0.003, bars 0.002.

Habitat.—North Pacific, Station 253, depth 3125 fathoms.

2. Cannartiscus amphicylindrus, n. sp.

Cortical shell thick walled, rough, with subregular, circular pores, twice to four times as broad as the bars; six to seven on the half meridian, ten to twelve on the half equator of each chamber. Polar tubes cylindrical, on the distal end open (broken off?) nearly as long as the main axis, somewhat narrower than the spherical medullary shell. Pores of the tubes much smaller than those of the chambers.

Dimensions.—Main axis (without tubes) 0.17, greatest breadth 0.12; pores 0.006 to 0.012, bars 0.003. Length of the polar tubes 0.15, breadth of them 0.03; pores 0.003, bars 0.002.

Habitat.—Pacific, central area, Station 268, 2900 fathoms; the same form occurs fossil in the rocks of Barbados.

Genus 162. Cannartidium,^[201] n. gen.

Definition.—Cyphinida with simple cortical shell and double medullary shell, with two hollow fenestrated polar tubes, opposite on both poles of the main axis.

The genus Cannartidium differs from Cannartiscus and Cannartus in the duplication of the medullary shell, which is composed of two concentric spheres or compressed lenticular spheroids. The three genera named form therefore one morphological series, with identical cortical shell, and only differing in the absence or presence of a simple or double medullary shell.

Subgenus 1. Cannartidella, Haeckel.

Definition.—Surface of the cortical shell smooth or a little rough, but without spines or fenestrated protuberances.

1. Cannartidium amphiconicum, n. sp.

Cortical shell thick walled, smooth with regular circular pores twice as broad as the bars; eight to nine on the half meridian, fifteen to sixteen on the half equator of each chamber. Polar tubes conical, with smaller pores, tapering towards the closed apex, about as long as one single chamber, at the base one-third as broad as the equatorial constriction. Both concentric medullary shells spherical. (Nearly identical with Cannartiscus amphiconiscus, Pl. 39, fig. 19, but differs in the possession of the double medullary shell.)

Dimensions.—Main axis of the cortical shell (without tubes) 0.15, greatest breadth 0.11; pores 0.009, bars 0.004; length of the polar tubes 0.08, basal breadth 0.04.

Habitat.—Pacific, western tropical part, Station 225, depth 4475 fathoms.

2. Cannartidium amphicanna, Haeckel.

"Curious twin Polycystin," Bury, 1862, Polycystins of Barbados, pl. xx. fig. 4.

Cortical shell thick walled, rough, with regular, circular pores, not broader than the bars; six to seven on the half meridian, ten to twelve on the half equator of each chamber. Polar tubes cylindrical, at the distal end open (broken off?), nearly as long as the main axis, about one-third as broad as the equatorial constriction. Both concentric medullary shells spherical.

Dimensions.—Main axis 0.14, greatest breadth 0.11; pores and bars 0.005; length of the polar tubes 0.13, breadth of them 0.03.

Habitat.—Fossil in the Barbados deposits.

3. Cannartidium amphisiphon, Haeckel.

? Haliomma amphisiphon, Ehrenberg, 1844, Monatsber. d. k. preuss. Akad. d. Wiss. Berlin, p. 267.

Cortical shell thick walled, rough, with irregular, roundish pores, twice to five times as broad as the bars; five to six on the half meridian, nine to ten on the half equator of each chamber. Polar tubes conical, with smaller pores, about as long as one single chamber, half as broad at the base as the equatorial constriction. (This deep-sea form is probably identical with that fossil species which Ehrenberg, in 1844, described as Haliomma amphisiphon, and which he afterwards, in 1875, erroneously identified with his Astromma entomocora (= Cypassis entomocora). But the figure given of the latter is quite different from the given diagnosis of the former.)

Dimensions.—Main axis of the cortical shell (without tubes) 0.13, greatest breadth 0.1; pores 0.006 to 0.12, bars 0.003; length of the polar tubes 0.07, basal breadth of them 0.04.

Habitat.—Tropical Atlantic, Antilles, Station 24, depth 390 fathoms; fossil in the Tertiary rocks of Bermuda.

4. Cannartidium bicinctum, n. sp. (Pl. 39, fig. 18).

Cortical shell thick walled, with a thickened ring-shaped protuberance in the greatest breadth of both chambers. Pores subregular, circular, twice to three times as broad as the bars; seven to eight on the half meridian, thirteen to fifteen on the half equator of each chamber. Polar tubes conical, with smaller pores, somewhat shorter than the greatest breath, nearly as thick at the base as the outer spheroidal medullary shell (fig. 18a).

Dimensions.—Main axis (without tubes) 0.12, greatest breadth 0.08; pores 0.003 to 0.006, bars 0.002; length of the polar tubes 0.08, basal thickness 0.03.

Habitat.—South Atlantic, Station 332, depth 2200 fathoms.

Subgenus 2. Cannartidissa, Haeckel.

Definition.—Surface of the cortical shell with conical fenestrated protuberances in the greatest breadth of both chambers.

5. Cannartidium mammiferum, n. sp. (Pl. 39, fig. 16).

Cortical shell-thin walled, having a circle of six to eight conical protuberances in the greatest breadth of both chambers, each of which exhibits a central apical pore, surrounded by a circle of six to eight oblique larger pores. Between the protuberances occur nine to ten pores on the half meridian of each chamber, circular, subregular, twice to three times as broad as the bars. Polar tubes cylindrical, conical at the closed end, with smaller pores, about as long as the greatest breadth of the chambers, as broad as the spherical outer medullary shell.

Dimensions.—Main axis (without tubes) 0.13, greatest breadth (including the protuberances) 0.1; pores 0.005 to 0.008, bars 0.003; length of the polar tubes 0.09, basal thickness 0.02.

Habitat.—Pacific, central area, Station 268, depth 2900 fathoms.

6. Cannartidium mastophorum, n. sp. (Pl. 39, fig. 17).

Cortical shell thin walled, of the same form and structure as in the foregoing species, differs from this mainly in the form of the polar tubes, which are not cylindrical but conical, tapering gradually from the base towards the closed apex. Besides this, the conical protuberances (six in the greatest periphery of each chamber) are more regular and acute, with smaller and more numerous pores. Both medullary shells are here also spherical.

Dimensions.—Main axis (without tubes) 0.14, greatest breadth (including the protuberances) 0.13; pores 0.006 to 0.009, bars 0.004; length of the polar tubes 0.07, basal thickness 0.03.

Habitat.—Pacific, central area, Station 266, depth 2750 fathoms.

Family XVI. Panartida, Haeckel (Pl. 40, figs. 1-9).

Definition.—Prunoidea with a four-jointed cortical shell, the external shell being divided by three parallel transverse constrictions into four chambers, in the centre enclosing two internal concentric shells (medullary shells). Central capsule cylindrical, commonly four-jointed (with three transverse annular constrictions).

The family Panartida (Pl. 40, figs. 1-9) is characterised by its four-jointed cortical shell, constantly composed of four chambers, lying one behind another in the elongated main axis. They are separated by three ring-like constrictions lying in three parallel transverse planes; the middle of these is the equatorial plane. In the centre of this latter lies constantly a double medullary shell.

The Panartida must be derived from the Cyphinida by further increase in the longitudinal or main axis, and by repetition of the equatorial constriction in two transverse planes parallel to it and at an equal distance from it.

The Medullary Shell is always double in this family, composed of two small concentric shells lying in the middle of the central capsule. They are either spherical or lenticular, compressed towards both poles of the main axis; sometimes the inner is spherical, the outer lenticular. From the equatorial circumference of the latter starts a number of radial beams, which perforate the central capsule, and are inserted into the equatorial constriction of the cortical shell. Commonly all radial beams lie in the equatorial plane, sometimes also a part of them on both sides of it.

The Cortical Shell is constantly composed of four completely latticed chambers, which are only separated by the three annular constrictions. In many species all four chambers have the same form and size (Pl. 40, fig. 3), but in the greater number of species both proximal (or central) chambers are different in size, shape, or structure from both distal (or polar) chambers. The cortical shell is either simple or double, composed of two concentric four-jointed shells; rarely it is triple or multiple, composed of three or more shells fitting one inside the other. Very often the outer cortical shell is incomplete, and only developed around the two proximal chambers of the complete inner cortical shell, both distal chambers of the latter remaining simple.

On both poles of the main axis often are developed solid spines (Panicium, Pl. 40, fig. 4) or hollow fenestrated tubes (Panarium, Pl. 40, fig. 9), as in the foregoing families. Besides this, the surface of the cortical shell may be armed with spines.

The Central Capsule of the Panartida is always cylindrical, on both poles hemispherical; commonly it is more or less distinctly four-jointed, with three ring-like constrictions corresponding to those of the enclosing cortical shell. From the inner surface of the latter it is separated by a thinner or thicker jelly-mantle.

Synopsis of the Genera of Panartida.

On both poles of the main axis neither peculiar polar spines nor fenestrated tubes. Cortical shell simple, 163. Panartus.

Cortical shell double or triple, 164. Peripanartus.

On both poles of the main axis a large apical spine or a group of polar spines. Cortical shell simple, 165. Panicium.

Cortical shell double or triple, 166. Peripanicium.

On both poles of the main axis a conical or cylindrical fenestrated tube. Cortical shell simple, 167. Panarium.

Cortical shell double or triple, 168. Peripanarium.

On both poles of the main axis neither peculiar polar spines nor fenestrated tubes.

Cortical shell simple,

163. Panartus.

Cortical shell double or triple,

164. Peripanartus.

On both poles of the main axis a large apical spine or a group of polar spines.

Cortical shell simple,

165. Panicium.

Cortical shell double or triple,

166. Peripanicium.

On both poles of the main axis a conical or cylindrical fenestrated tube.

Cortical shell simple,

167. Panarium.

Cortical shell double or triple,

168. Peripanarium.

Genus 163. Panartus,^[202] n. gen.

Definition.—Panartida with simple cortical shell and double medullary shell, without polar spines or tubes on both poles of the main axis.

The genus Panartus represents the common ancestral form of all Panartida, as all other genera of this subfamily must be derived from it and are only further developmental stages, from an ontogenetic as well as from a phylogenetic point of view. The cortical shell of Panartus is constantly composed of four fenestrated chambers jointed to one another in the main axis; both proximal chambers are separated from one another by the equatorial ring-like constriction, in the centre of which lies the double medullary shell; both distal chambers are separated from the former by two other annular constrictions (in planes parallel to the equatorial plane). All four chambers may exhibit the same (kidney-shaped) form and structure (in the subgenera Panartella and Panartoma); or the proximal chamber may differ more or less in shape and size from the distal (in the subgenera Panartissa and Panartura). The outer surface of the cortical shell is sometimes smooth (as in Panartella and Panartissa), at other times spiny or thorny (as in Panartoma and Panartura). The double medullary shell is sometimes spherical, or commonly compressed at both poles and spheroidal or lenticular.

Subgenus 1. Panartella, Haeckel.

Definition.—Surface of the cortical shell smooth, without spines or thorns. All its four chambers exhibit nearly the same form and structure.

1. Panartus tetraplus, n. sp.

All four chambers of the cortical shell of the same form, size, and structure, kidney-shaped, twice as broad as long. Pores rather regular, hexagonal, all nearly of the same size and form, four times as broad as the thin bars; five to six pores on the half meridian, nine to ten on the half equator of each chamber. Surface of the cortical shell smooth, its main axis three times as long as its equatorial axis (in the median constriction). Both concentric medullary shells spherical; the equatorial axis of the outer half as long as that of the cortical shell. (All four chambers of this species have the same appearance as the two proximal chambers of Panartus diploconus, Pl. 40, fig. 1.)

Dimensions.—Main axis of the cortical shell 0.21, equatorial axis 0.07; breadth of every chamber 0.09; meshes 0.013, bars 0.03.

Habitat.—Central area of the Pacific, Stations 270 to 274, depth 2350 to 2925 fathoms.

2. Panartus tetracolus, n. sp.

All four chambers of the cortical shell of the same form, size, and structure, kidney-shaped, twice as broad as long. Pores regular, circular, with hexagonal frame, twice as broad as the bars; six to seven pores on the half meridian, ten to twelve on the half equator of each chamber. Surface of the cortical shell smooth; its main axis three times as long as the equatorial axis. Both concentric medullary shells spheroidal, somewhat compressed at both poles; the equatorial axis of the outer almost equals half that of the cortical shell. (All four chambers of this species exhibit the structure of the two proximal chambers of Peripanartus amphiconus, Pl. 40, fig. 5.)

Dimensions.—Main axis of the cortical shell 0.24, equatorial axis 0.08; breadth of every chamber 0.01; meshes 0.01, bars 0.005.

Habitat.—Equatorial Atlantic, Station 348, depth 2450 fathoms.

3. Panartus tetrameres, n. sp.

All four chambers of the cortical shell of the same form, size, and structure, kidney-shaped, twice as broad as long. Pores rather regular, circular, without hexagonal frame, about as broad as the bars; five to six pores on the half meridian, ten to twelve on the half equator of each chamber. Surface of the cortical shell smooth, its main axis three times as long as the equatorial axis. Both concentric medullary shells spheroidal, compressed; the outer half as broad as the constriction. (This species is very much like Ommatocampe increscens, Stöhr, 1880, loc. cit., Taf. ii. fig. 2, and may be considered as the ancestral form of it.)

Dimensions.—Main axis of the cortical shell 0.2, equatorial axis 0.065; breadth of every chamber 0.08; meshes and bars 0.005.

Habitat.—Fossil in the Tertiary rocks of Sicily, Caltanisetta, Haeckel.

4. Panartus tetraphalangus, n. sp.

All four chambers of the cortical shell of the same form, size, and structure, kidney-shaped, twice as broad as long. Pores irregular, polygonal (mostly pentagonal or hexagonal), four to eight times as broad as the thin bars; four to seven on the half meridian, eight to fifteen on the half equator of each chamber. Surface of the cortical shell smooth, its main axis three times as long as its equatorial axis. Both concentric medullary shells compressed, the outer, half as broad as the constriction.

Dimensions.—Main axis of the cortical shell 0.26, equatorial axis 0.09; breadth of every chamber 0.12; meshes 0.003 to 0.02, bars 0.001 to 0.003.

Habitat.—Fossil in the rocks of Barbados, Haeckel.

5. Panartus tetrathalamus, n. sp. (Pl. 40, fig. 3).

All four chambers of the cortical shell of the same form, size, and structure, kidney-shaped, twice as broad as long. Pores irregular, roundish, twice to three times as broad as the bars; a circle of larger pores at the base of both distal chambers; five to six pores on the half meridian, ten to twelve on the half equator of each chamber. Surface of the cortical shell smooth; its main axis two and a half times as long as the equatorial axis. Both medullary shells spheroidal, compressed, the outer one-third as broad as the constriction. (In the specimen figured spines begin to arise from both distal chambers; this forms a transition to Panartus quadrijugus.)

Dimensions.—Main axis of the cortical shell 0.18, equatorial axis 0.07; breadth of every chamber 0.09; meshes 0.003 to 0.01, bars 0.002 to 0.004.

Habitat.—Cosmopolitan; Mediterranean, Atlantic, Pacific, in various depths.

Subgenus 2. Panartissa.

Definition.—Surface of the cortical shell smooth, without spines or thorns. Both its proximal chambers differ in form and structure from the two distal chambers.

6. Panartus diploconus, n. sp. (Pl. 40, fig. 1).

Both proximal chambers nearly ellipsoidal, one and a half times as broad as long, with regular hexagonal pores, four times as broad as the bars; five to six pores on the half meridian, nine to ten on the half equator of each chamber. Both distal chambers conical, with a circle of ten to twelve large square pores at the base; the other pores very small and numerous, roundish, sixteen to twenty in the height of each cone, and the same number on the half periphery of its base. Both concentric medullary shells compressed, the outer, half as broad as the constriction of the cortical shell, the surface of which is quite smooth.

Dimensions.—Total length of the shell (or main axis) 0.34; greatest breadth of each chamber 0.09; pores of the proximal chambers 0.013, bars 0.003; pores and bars of the distal chambers 0.003; large basal square pores 0.02.

Habitat.—Pacific, central area, Station 272, depth 2600 fathoms.

7. Panartus amphiconus, n. sp.

Both proximal chambers nearly kidney-shaped, one and a half times as broad as long, with regular, circular pores, with hexagonal frames, twice as broad as the bars; six to seven pores on the half meridian, ten to twelve on the half equator of each chamber. Both distal chambers conical, with a circle of ten to twelve very large pores at the base; the other pores very small, roundish, ten to fifteen in the height of each cone, twenty to thirty on the half basal periphery. Both concentric medullary shells compressed, the outer one-third as broad as the constriction of the cortical shell, whose surface is smooth. (This species resembles Peripanartus amphiconus, Pl. 40, fig. 5, but is without the surface spines and the outer envelope.)

Dimensions.—Total length of the shell 0.28; greatest breadth of the proximal chambers 0.1, of the distal chambers 0.14; pores of the former 0.008, of the latter 0.004; bars of both 0.003 to 0.005.

Habitat.—North Pacific, Station 244, depth 2900 fathoms.

8. Panartus fusiformis, n. sp.

Both proximal chambers nearly ellipsoidal, one and a half times as long as broad, with irregular, roundish pores, twice to three times as broad as the bars; eight to ten pores on the half meridian, twelve to fifteen on the half equator of each chamber. Both distal chambers hemiellipsoidal or egg-shaped, somewhat higher and narrower than the proximal chambers, with a circle of larger square pores at their base; the other pores roundish and very irregular. Both medullary shells spheroidal, one-third as broad as the constriction of the cortical shell, whose surface is quite smooth. (This species is similar to Peripanartus atractus, Pl. 40, fig. 7, but is without the superficial spines and the equatorial girdle-like envelope of the latter.)

Dimensions.—Total length of the shell 0.25 to 0.3; greatest breadth (in the equator of the proximal chambers) 0.08 to 0.1; pores of the proximal chambers 0.008 to 0.012, pores of the distal chambers half their size, bars 0.002 to 0.006.

Habitat.—North Pacific, Station 237, surface.

9. Panartus profundissimus, Haeckel.

Ommatocampe profundissima, Ehrenberg, 1872, Abhandl. d. k. Akad. d. Wiss. Berlin, p. 297, Taf. viii. fig. 6.

Both proximal chambers nearly ellipsoidal, with irregular, polygonal pores, six to eight times as broad as the bars; four to five pores on the half meridian, eight to nine on the half equator of each chamber. Both distal chambers hemispherical, with a very delicate irregular network. Medullary shells spherical; surface of the shell smooth.

Dimensions.—Total length of the shell 0.15; greatest breadth in the equator of the proximal chambers 0.08; pores of the proximal chambers 0.015, bars 0.002.

Habitat.—Philippine Sea, depth 3300 fathoms, Ehrenberg; Station 213, depth 2050 fathoms.

Subgenus 3. Panartoma, Haeckel.

Definition.—Surface of the cortical shell thorny, covered with scattered spines. All its four chambers exhibit the same form and structure.

10. Panartus quadriceps, n. sp.

All four chambers of the cortical shell of the same form, size, and structure, kidney-shaped, twice as broad as long. Pores rather regular, circular, with hexagonal frames, twice to three times as broad as the bars; six to seven pores on the half meridian, ten to twelve on the half equator of each chamber. Surface spiny; from the corners of the hexagonal frames (between every three pores) arise short radial spines. Both medullary shells spherical, the outer one-third as broad as the constriction of the cortical shell. (All the four chambers of this species have the same form as the two proximal chambers of Peripanartus amphiconus, Pl. 40, fig. 5.)